1. Field of the Invention
The present invention relates to an alarm information providing apparatus for a vehicle, and in particular, to an apparatus which provides alarm information to a driver of a vehicle upon request from the driver.
2. Description of the Related Art
When changing traffic lanes or driving courses, drivers of vehicles such as automobiles confirm the circumstances behind the vehicles through back mirrors and side mirrors or with their eyes. Unfortunately, there is a case that the backside circumstances are not accurately recognized because of a driver's carelessness. In this case, if the driver changes the course without confirming the backside circumstances, the vehicle may abnormally approach another approximate vehicle driving behind it. In order to avoid such a case, apparatuses for providing surrounding information of a driving vehicle to the driver has been conventionally developed.
Those apparatuses include a means for detecting information related to the surrounding circumstances, for example, presence of other vehicles driving behind or distance between the own vehicle and the other vehicles. The apparatuses have a function of providing alarm information to the driver by using information recognized by hearing such as buzzers and voices, or information recognized by visual such as lamp flashing or images. A specific example will be explained with reference to FIG. 11. FIG. 11 is a function block diagram showing a conventional alarm information providing apparatus for a vehicle 101.
The alarm information providing apparatus for a vehicle 101 shown in FIG. 11 includes, a means for recognizing surrounding circumstances of a vehicle, and a means for providing alarm information to the driver of the vehicle according to the surrounding information provided by the means for recognizing surrounding circumstances. The means for recognizing surrounding circumstances consists of a back camera 102 for taking in the circumstances behind the vehicle as image data, and an object detecting unit 105a and an object contact possibility determining unit 105b which are incorporated in a processing unit (controller) 105 for processing the image data taken by the back camera. The object detecting unit 105a detects another vehicle driving behind, and the object contact possibility determining unit 105b performs determination of the contact possibility between the own vehicle and the other vehicle. Once the object contact possibility determining unit 105b determines that the own vehicle has a possibility to contact the other vehicle driving behind, and the own vehicle needs to take precautions against it, an alarm information providing unit 103 such as a lamp 103a or a buzzer 103b is output-controlled by an alarm information output controller 105c in the processing unit 105. Consequently, information for urging precautions is provided to the driver H (alarm information providing unit). Note that the means for recognizing surrounding circumstances will be explained in detail in embodiments of the present invention described later.
As the aforementioned means for providing alarm information, the Japanese Patent No. 2906101 discloses a means in which a device for oscillating the acceleration pedal is added for an alarming purpose. Further, the Japanese Patent Laid-open No. 9-220975 discloses a device for oscillating the steering wheel, the breaking pedal or the acceleration pedal for an alarming purpose as well. These devices have not been used generally from the point of practicability.
Moreover, the Japanese Patent No. 2641562 discloses a device which recognizes, when the blinker lever is operated in either direction, the backside vehicle circumstances of the corresponding direction and informs alarm information.
However, there may be a case that information, related to circumstances where a danger may happen by changing the course or turning right/left, is provided to the driver when it is not necessary for the driver. In such a case, a lamp or a buzzer as the alarm information may cause discomfort to the driver or passengers. Particularly, when an alarming direction is irrelevant to the driving direction of the vehicle, the driver does not need to confirm it, so that the alarm information itself is worthless.
Further, considering a course change with an automobile, for example, the period from the time when the driver decides to change the course to the time the driver actually performs the change is generally short. Therefore, if the information is presented to the driver by a conventional visually indicating means or the like, there may be a case that the driver cannot adequately respond to the information by sufficiently recognizing the information. That is to say, since the period from flashing the blinker to actually changing the course is extremely short, it may be difficult to take an appropriate measure corresponding to the alarm information if the alarm information is presented after the blinker is flashed.
If countermeasures are taken by, for example, speeding up the presenting timing of the information in order to avoid the aforementioned problems, there may be cases that the information quality degrades or the driver is annoyed by the visual or audio information. As a result, new problems, such as an increase in a burden of the driver to recognize information and a divergence between the information contents and the driver's recognition, arise.